Rigid articles having a well-defined corner

ABSTRACT

A blow-molded article having improved well-defined corners is provided.

FIELD OF THE INVENTION

The present invention relates to certain PET copolymer resin containinginjected (stretch) blow molded rigid articles with improved definedcorners.

BACKGROUND OF THE INVENTION

Rigid articles, particularly containers, made of thermoplastic materialshave been used to package a wide variety of consumer goods products,such as in the cosmetic, shampoo, laundry, and food categories. For sucharticles, having a unique and desirable shape is important. One designelement in rigid articles is the use of well-defined corners. Thesewell-defined corners are used to define, for example, a shoulder portionof a bottle. In a specific example, the VIDAL SASSON® (The Procter &Gamble Company) shampoo bottle has well-defined corners (alternatively“sharp corners”) near the top of the bottle that contribute to theiconic look of the bottle. The so called “square shoulders” provide aunique point of equity (in the myriad of shampoo bottles available inthe marketplace) that are recognized by consumers.

Many rigid articles, such as bottles, are made with resins: PE(Polyethylene), PP(Polypropylene) or PETG [Poly (ethyleneterephthalateco-1,4-cylclohexylenedimethylene)], or the combinationthereof. These resin(s) are co-extruded (along with additional multiplematerials) into a parison at a temperature higher than the meltingtemperature of the resin. After the parison is formed, it is blown withpressure against a mold to form the desired three-dimensional shape ofthe article. The blow molded article demolds around ambient temperature.Often PETG is used in the outermost layer of the parison/blown articleto deliver a high gloss effect. These aforementioned resins aregenerally able to produce well-defined corners because the associatedextrusion blow molding (EBM) process requires the resin material to flowand to be blown at a temperature considerably higher than the resin'smelting temperature. Consequently, the heated resins flow easily therebypenetrating the limited spaces of the mold that define the correspondingcorner(s) of the rigid article.

However, there are at least one or more disadvantages in using the EBMplatform (and the aforementioned resins). Since EBM requires multipledifferent resins to deliver high gloss effects to the article, thecombination of materials may pose recycling challenges. Translucency ortransparency is sometimes a desired appearance effect in the article.Generally, standard EBM process has challenges in providing this effect,especially when PE or PP resin is used. The use of multiple number ofresins and/or other materials to provide any of these aforementionedeffects increases complexity and cost from a processing as well aslogistical perspectives.

There is a growing trend in the use of PET, or modified PET comprisingmaterials, in an injection (stretch) blow molding (IBM or ISBM) process.Generally, PET in an I(S)BM platform has flexibility in deliveringdifferent appearance effects to articles. These effects include hightransparency to high opacity; and mirror-like shininess to a mattefinish. However, a problem with typical PET in the I(S)BM platform isthe ability to form well-defined corner(s). Without wishing to be boundby theory, the problem with forming these well-defined corners isbecause the PET resin is typically blown at relative low temperature,e.g., generally between glass-transition temperature (“Tg temperature)and cold-crystallization peak temperature (“T_(cc) temperature”).Consequently, this resin is hard to deform and difficult to be blowninto the corresponding corners of the mold.

Accordingly, there is a need to have one or more of the advantagesassociated with traditional PET materials and I(S)BM platform but alsohaving the ability to form articles with well-defined corner(s) (that isotherwise generally available with PE/PP and EMB platform) as to delivera fuller palette of design options to articles.

SUMMARY OF THE INVENTION

The present invention is based, in part, on the surprising discoverythat using certain PET copolymer resins, in the outermost layer of anarticle, of a defined elastic modulus (E′) is predictive, at least inpart, of the ability of the PET copolymer resin's ability to producerigid containers with a well-defined corner (when made by I(S)BM) of adesirable thickness.

E′ is measured at the temperature equal to the cold-crystallization peaktemperature (T_(cc)) minus 15° C. at 1 Hertz (Hz). This temperature ischosen because it roughly corresponds to the temperature used forblowing (and stretching) in the I(S)BM platform, and thus is importantand relevant in characterizing the resin in forming the well-definedcorner of desired thickness during this process step. It is thissurprising observation that led, at least in part, to the discovery ofthe present invention. Accordingly, one aspect of the invention providesa rigid blow molded article comprising: (a) sides of the article formingat least one corner wherein the corner is characterized by amathematically fitting a sphere of best fit into the corner so there isat a circular arc section in the at least one corner, wherein radius ofcurvature of the sphere of best fit is less than 5.7 mm; (b) said cornerhaving an average thickness from 0.1 mm to 1 mm; and (c) said sidesforming said corner comprises at least an outer layer of an outer layermaterial having an elastic modulus (E′) less than 370 MPa measured bydynamical mechanical analysis (“DMA”) per ASTM method D4065, with afrequency sweep conducted at the fixed temperature of thecold-crystallization peak temperature (“T_(cc)”) of the PET copolymerresin minus 15° C. (T_(cc)−15° C. temperature) at 1 Hz, wherein theT_(cc) is measured by way of differential scanning calorimetry (“DSC”)at a temperature ramp rate of 10° C. per minute.

One potential advantage, of an example of the present invention, is arigid blow molded article having a desirable barrier property (and yetstill provide a well-defined corner).

One or more examples of the present invention may have one or more ofthe following advantages particularly as compared to EBM platform (andassociated resins).

One potential advantage, of an example of the present invention, isimproved recyclability.

Another potential advantage, of an example of the present invention, isreduced formulation complexity.

Another potential advantage, of an example of the present invention, isincreased translucency or even transparency.

Another potential advantage, of an example of the present invention, isincreased shine, especially with minimizing the use of additives.

These and other features, aspects, and advantages of examples of thepresent invention will become evident to those skilled in the art fromthe detailed description which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly defining anddistinctly claiming the invention, it is believed that the inventionwill be better understood from the following description of theaccompanying figures:

FIG. 1 is a perspective view of a three-dimensional image datareconstructed from two-dimensional CT scanning data of the upper portionof a represented bottle with a well-defined corner highlighted;

FIG. 2A is a perspective view of a software image of a sphere of bestfit mathematically fitting into the corner of FIG. 1;

FIG. 2B is a front view of the image of FIG. 2A;

FIGS. 3A, 3B, and 3C are three-dimensional image data reconstructed fromtwo dimensional CT scanning data to describe the average thickness ofthe corner (representative example shown in FIG. 1) for a comparativeexample (FIG. 3A) and inventive examples A and B (FIGS. 3B and 3C,respectively); and

FIG. 4 is differential scanning calorimetry data of PET resin (of thecomparative example), and PET copolymer resins (of the inventiveexamples A and B).

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term “article” herein refers to an individual blowmolded object for consumer usage, e.g., a shaver, a handle, atoothbrush, a battery, an applicator, or a container suitable forcontaining compositions. Preferably the article is a container.Non-limiting examples of which include a bottle, box, carton, jar, cup,cap, and the like. The term “container” is used herein to broadlyinclude elements of a container, such as a closure or dispenser of acontainer. The compositions contained in the container may be any of avariety of compositions including, but not limited to, detergents (e.g.,laundry detergent, fabric softener, dish care, body and hair care,shampoo), beverages, powders, paper (e.g., tissues, wipes), beauty carecompositions (e.g., cosmetics, lotions), medicinal, oral care (e.g.,tooth paste, mouth wash), and the like. The container may be used tostore, transport, or dispense compositions contained therein.Non-limiting examples of volumes containable within the container arefrom 10 ml to 5000 ml, alternatively from 100 ml to 4000 ml,alternatively from 200 ml to 2,000 ml, alternatively from 300 ml to1,200 ml, or 400 ml to 1,100 ml. In another non-limiting example, thearticle is a shampoo bottle capable of holding about 600 ml to about 900ml of a shampoo composition.

As used herein, the term “injection blow molding” refers to amanufacturing process by which hollow cavity-containing plastic articlesare made. In general, there are two main types of injection blowmolding: Injection Blow Molding (IBM) and Injection Stretch Blow Molding(ISBM). The blow molding process typically begins by shearing or meltingplastic and forming it into an article precursor. The term “articleprecursor”, as used herein, refers to the intermediate product form ofplastic that is affixed into a blow molding mold. The article precursoris typically either an extruded parison or an injected molded preform.The melted or heated article precursor is then fixed into the blowmolding mold, and its opening is blown with compressed air. The airpressure stretches and blows the plastic out to conform to the shape ofthe mold. Once the plastic has cooled, the mold opens and the formedrigid article is ejected. Generally, the formed article can be made ineither: a single machine; or in two machines (i.e., first an injectionmolding machine (typically about 260° C.) and then (stretch) blow molded(80° C. to 110° C.) in another separate machine). The blow molding (andstretching) temperature is typically about 15° C. below the T_(cc)temperature of the resin(s). A typical blowing pressure is about 10 MPato about 50 MPa, alternatively about 30 MPa. The stretch ratio is fromabout 1 to about 30, or from 2 to 20, or from 3 to 10, alternativelyfrom 3 to 6. In one example, the rigid article of the present inventionis made by stretch blowing the injection molded preform at a temperaturegreater than 85° C. and less than 115° C.

Making Comparative and Inventive Examples

Three bottles, having a 750 ml fill-line, with four corners are made ina two-step ISBM process. The mold is the same for the three bottlesexcept the comparative example is made with a standard PET grade resinwhereas the inventive examples A and B are made with a PET copolymerresin. A colorant is added. All three bottles are a single layer (orrespective resin). The inventive examples have improved well-definedcorners relative to comparative example. The making conditions aregenerally the same for the three bottles and are summarized herein.Preforms are injected molded with each type of resin material. Thepreform has thickness of about 4-5 mm with a cycle time of 40 seconds at270-280° C. temperature. The mold, to blow mold the preforms into thesubject bottles, is among one that is used to make the commercializedVIDAL SASSON® 750 ml shampoo bottle. Notably the “shoulders” of thebottle are defined by two sets of opposing corners. One set of opposingcorners are obtuse corners while the other set of opposing corners areacute corners. An example of a bottle made from the mold is shown inFIG. 1 which is a three-dimensional image data reconstructed from twodimensional CT scanning data of the upper portion of a representedbottle with one of the acute corners highlighted. The bottle has fourcorners with a set of acute corners opposing each other (and obtusecorners opposing each other). In the mold, the radius to make each ofthese four corners is about 0.1 mm. The preforms are reheated to atemperature of 85° to 95° C. in the comparative example and theinventive example A, and about 110° to 120° C. in the inventive exampleB, in the reheating oven/channel at a line speed of 2.5 mm/second beforebeing stretch blown in to the subject mold at a blowing pressure of 34kg/f. The approximate temperature used for both the blow molding andstretching of comparative and inventive examples are: 87° C. for thecomparative example; 93° C. for inventive example A and 110° C. forinventive example B. The bottles are a single layer of the subject PETresin (comparative) or PET copolymer resin (inventive). The stretchratio is about 4.2.

Radius of Curvature

The present invention is directed to rigid, injected (stretch) blowmolded, articles having an improved well-defined corner as compared tothose articles made from classic PET and an I(S)BM platform. The sidesof the article form the corner. The term “corner,” is used herein thebroadest sense to include embossing or other patterns of the rigidarticle. A corner of the present invention is characterized bydetermining a radius of curvature of a circular arc of a sphere that ismathematically a best fit to the exterior surface of the well-definedcorner. A suitable mathematical approach is using the method of leastsquares (which is a standard approach in regression analysis). Inpractice, X-ray microtomography is used to recreate a virtual model(i.e., three-dimensional (“3D”) model) of the article with specificmention to the corner. Other terms to describe this approach includehigh-resolution micro CT, high resolution x-ray tomography,micro-computed tomography, and similar terms. To calculate the radius ofcurvature from the recreated virtual model of the corner, commerciallyavailable software can be used. One aspect of the invention provides aradius of curvature less than 5.7 mm, preferably at or less than 5 mm,more preferably at or less than 4.6 mm, even more preferably at or lessthan 4 mm, yet even more preferably at or less than 3.6 mm, yet evenstill more preferably at or less than 3.5 mm; alternatively, from 0.5 mmto less than 5.7 mm, or from 1 mm to 5.5 mm, or from 1 mm to 5 mm, orfrom 1.5 mm to 4.5 mm, or from 2 mm to 4 mm; alternatively, combinationsthereof.

The three bottles of the comparative example and the inventive examplesA and B are scanned by way of micro-CT and a 3D computer image isgenerated. A geometric analysis, including radius curvature of thecorner and thickness of the corner, is conducted. Briefly the micro-CTinstrument is a cone beam microtomography with a shielded cabinet. Amaintenance free X-ray tube is used as the source with an adjustablediameter focal spot. The X-ray beam passes through the sample, wheresome of the X-rays are attenuated by the bottle sample. The extent ofattenuation correlates to the mass of material the X-rays pass through.The transmitted X-rays continue to the digital detector array andgenerate a two-dimensional (2D) projection image of the sample. A 3Dimage of the sample is generated by collecting individual projectionimages of the sample as it is rotated, which are then reconstructed intoa single 3D image. The instrument is interfaced with a computer runningsoftware to control the image acquisition and save the raw data.

The samples are scanned by GE Phoenix vltomelx m CT scanner (GE Sensing& Inspection Technologies GmbH Niels-Bohr-Str.7 31515 Wunstorf, Germany)The sample stands on a rotation sample stage, wherein the distancebetween sample and X-ray source is adjusted to ensure the resolution is127 um/voxel. 2D projection is acquired at—2014*2014 pixels—with thefollowing parameters: micro-tube; voltage:180 kV; current: 120 μA; tubemode: 1; timing: 500 ms; averaging: 4; skip frames: 1; number of images:2000. A series of 2D projections are reconstructed to 3D image data bysoftware accompanying the instrument. A surface file (.obj) is createdby software VG Studio MAX 3.0 (Volume Graphics GmbH, Germany) forfurther geometric analysis.

As illustrated in FIG. 1, the built-in curvature map feature in GeomagicStudio 2013 is used to define the corners (3, 5, 7, 9) of the upperportion of a bottle (1). The bottle (1) has opposing acute corners (3,5) and opposing obtuse corners (7, 9). The first acute corner (3)opposes the second acute corner (5). The first obtuse corner (7) opposesthe second obtuse corner (9). The software uses the crease angle betweenadjacent polygons on the scan surface to display the curvature map.Turning to FIGS. 2A and 2B, the corner (3) of the bottle (1) ischaracterized by determining a radius of curvature of a circular arc(13) of a sphere (11) that is mathematically a best fit to the exteriorsurface of the corner (3). It can be mathematically fit by using theleast squares method. The built-in 3D Comparison feature in GeomagicQualify 2013 is used to calculate the deviation between the best-fitspheres and the scan data. The maximum deviation is about 0.5 mm FIGS.2A and 2B show where different regions of the sphere (11) mathematicallyfit into the corner. FIG. 2A is a perspective view whereas FIG. 2B is afront view. Generally, there are three ways the sphere (11) can fit in acorner (3): a perfect fit; a fit where the sphere (11) is inside thecorner (3); or a fit where the sphere (11) is outside the corner (3). Aradius of curvature of a circular arc (13) is provided of a sphere (11)that is mathematically placed as a best fit to the exterior surface ofthe corner. Generally, the more well-defined (i.e., sharper) the cornerthe smaller the sphere, and consequently the smaller radius of acircular arc (13). FIGS. 2A and 2B are directed to an acute corner (3)of the comparative example.

Radius of curvature for the comparative example and for the inventiveexamples are provided. As summarized in Table 1 below, the radius ofcurvature for the comparative example is 6.4 mm for the first acutecorner and 5.7 mm for the opposing second acute corner. An improvedwell-defined corner is demonstrated for inventive example A having aradius of curvature of 4.6 mm for the first acute corner (an improvementof 1.8 mm over the comparative example). An even more improvedwell-defined corner is demonstrated for inventive example B having aradius of curvature of 3.5 mm for the first acute corner (an improvementof 2.9 mm over the comparative example) and 3.6 mm for the opposingsecond acute corner (an improvement of 2.2 mm).

In one example, the article has at least one corner, preferably at leasttwo corners, more preferably at least three corners, yet even morepreferably at least four corners. Alternatively, the article has atleast four corners wherein each of the four corners have the samedimensions (i.e., the same radius of curvature). Alternatively, thearticle contains at least four corners, where two corners (of the atleast four corners) are acute corners and two corners (of the remainingat least two corners) are obtuse corners, wherein the acute corners arewell-defined corners as defined herein. Preferably the acute cornershave the same dimensions and the obtuse corners have the samedimensions. More preferably the four corners are in the same plane, andpreferably wherein the plane is orthogonal to the article's longitudinalaxis. Preferably the article is a container. More preferably thecontainer is a bottle. Yet more preferably the corners help define theshoulders of a bottle.

Thickness

Similar software, as described above for the radius of curvature, can beused to determine the average thickness of the corner. One aspect of theinvention provides for an average thickness of the corner from 0.1 mm to1 mm, preferably from 0.1 mm to 0.9 mm, more preferably from 0.2 mm to0.8 mm, even more preferably from 0.3 mm to 0.7 mm, alternatively from0.4 mm to 0.6 mm.

The average thickness of the acute corners of comparative example andthe inventive examples A and B is determined by using a KINETIC VISIONproprietary process to create the “.THK” file. Other commercial softwarepackages (e.g., Geomagic Qualify, VGStudio MAX, etc.) can be used.Average thickness results are shown in: FIG. 3A for comparative example;FIG. 3B for inventive examples A; and figure C for inventive example B.Thickness results are also provided in Table 1 below.

TABLE 1 Geometric analysis of comparative example and inventive examplesA and B are provided. Comparative Inventive Inventive Ex. Ex. A Ex. BRadius of curvature 6.4 mm 4.6 mm 3.5 mm of first acute corner Radius ofcurvature 5.7 mm 5.7 mm 3.6 mm of opposing second acute corner Averagethickness 0.35 mm 0.55 mm 0.42 mm of first acute corner Averagethickness 0.36 mm 0.53 mm 0.45 mm of opposing second acute cornerElastic Modulus (E′).

Viscoelastic characteristics of the outer layer material, preferablywherein the outer layer material comprises a PET copolymer resin, ischaracterizable by way Dynamic Mechanical Analysis (“DMA”). One aspectof invention provides for the PET copolymer resin having an elasticmodulus (E′) less than 370 MPa measured by DMA per ASTM method D4065,with a frequency sweep conducted at the fixed temperature of thecold-crystallization peak temperature (“T_(cc)”) of the PET copolymerresin minus 15° C. (T_(cc)−15° C. temperature) at 1 hertz (1 Hz),wherein the T_(cc) is measured by way of differential scanningcalorimetry (“DSC”) at a temperature ramp rate of 10° C. per minute. DSCis described in further detail below. Preferably said E′ is at or lessthan 350 MPa, preferably less than 300 MPa, more preferably less than250 MPa, more preferably less than 200 MPa, more preferably less than150 MPa, more preferably less than 140 MPa, more preferably less than135 MPa. More preferably said E′ is from 10 MPa to less than 350 MPa,preferably from 25 MPa to 300 MPa, more preferably from 50 MPa to 250MPa, more preferably from 60 MPa to 200 MPa, alternatively from 75 MPato 150 MPa, alternatively from 100 MPa to 140 MPa, alternatively from110 MPa to 135 MPa. In one example, the outer layer material may becomprised of two or more polymeric resins. In another example, the outerlayer material is a single polymer resin. In yet another example, theouter layer is a single layer and a single polymer resin.

Elastic modulus (E′) describes tensile elasticity, or the tendency of anobject to deform along an axis when opposing forces are applied alongthat axis. It is defined as the ratio of tensile stress to tensilestrain. Without wishing to be bound by theory, E′ reflects a material'selasticity and stiffness, wherein the lower value likely means a betterdeformation ability of the PET copolymer resin, which likely helpscontribute to forming the corner. Generally, the lower value of E′, themore well-defined (i.e., sharper) the corner in the context of thepresent invention.

E′ is assessed for the three samples. The DMA instrument employed isDMA/SDTA861e, Mettler-Toledo, BTC-1278. The apparatus is operated in thetension deformation mode with an imposed displacement lower than 100 umand tension force lower than 10 N to remain samples to deform in thelinear domain. A DMA frequency sweep is conducted at the followingtemperature: cold-crystallization peak temperature (T_(cc)) minus 15° C.(T_(cc)−15° C. temperature) and at 1 Hz. In turn, T_(cc) is determinedfor each of the three samples (comparative and inventive A and B) by wayof DSC at a temperature ramp rate of 10° C. per minute. DSC is describedin further detail below. The T_(cc)−15° C. temperature is selected asthe fixed temperature of the frequency sweep because this temperature isgenerally close to the blow molding (and stretching). Without wishing tobe bound by theory, the properties of the outer layer material at thistemperature is important in providing the desirable well-defined cornerand thickness of the inventive containers described herein.

As part of the DMA results, the dimensions of the samples taken from thethree example bottles are considered (i.e., unifying the dimensions) incalculating the elastic modulus (E′). For context, samples were takennear a corner of the respective bottles and have dimensions of about 9mm in length, 1 to 1.2 mm in thickness, and 2.5 to 3.5 mm in width. DMAresults are provided in Table 2 below. Briefly, the comparative examplehas an E′ of 380.835 MPa, whereas inventive examples A and B have an E′of 243.261 MPa and 130.691 MPa, respectively.

TABLE 2 Viscoelastic Characteristics of the resin of comparative exampleand inventive examples A and B are provided. Comparative InventiveInventive Ex. Ex. A Ex. B PET copolymer resin Standard PET¹ EN099²SC830³ Blow molding/ ~87° C. ~93° C. ~110° C. stretching temperatureT_(cc) - 15° C. 87.51° C. 95.95° C. 117.26° C., E′⁴ at 380.835 MPa243.261 MPa 130.692 MPa T_(cc) - 15° C. and at 1 Hz ¹Product CR-8863,Lot No. 117170103, manufacturer by China Resources Packaging MaterialCo., Ltd (Changzhou, China). ²Product Eastar ™ Copolyester EN099,manufactured by Eastman. ³Product SC830, manufacturer Eastman. ⁴ASTMD4065Differential Scanning CalorimetryOne aspect of the invention provides for the outer layer material,preferably wherein the outer layer comprises the PET copolymer resin,having a cold-crystallization peak temperature (“T_(cc)”) greater than105° Celsius, wherein the T_(cc) is measured by way of differentialscanning calorimetry (“DSC”) at a temperature ramp rate of 10° C. perminute. The DSC method is generally in accordance with ASTM methodD3418, but any conflicts between the ASTM method and the descriptionprovided herein, the present description controls. Preferably saidT_(cc) for the outer layer (preferably wherein the outer layer comprisesthe PET copolymer resin) is greater is at or greater than 110° C.,preferably greater than 120° C., more preferably greater than 125° C.,alternatively said T_(cc) is from 105° C. to 150° C., or 120° C. to 150°C., or alternatively 125° C. to 145° C.

Another aspect of the invention provides for the PET copolymer resinhaving a percentage of crystallinity of less than 19%, wherein thepercentage of crystallinity is determined the by formula: %crystallinity=[ΔHm−ΔHc]/ΔHm°*100%; wherein ΔHm is the heat of melting(J/g) and ΔHc is the heat of cold crystallization (J/g), and wherein ΔHmand ΔHc are determined by differential scanning calorimetry at atemperature ramp rate of 10° C. per minute, and wherein ΔHm° isreference value of 140.1 J/g (wherein 140.1 J/g represents the heat ofmelting PET polymer if the PET were 100% crystalline). Preferably thepercentage of crystallinity is less than 17%, more preferably less than15%, more preferably less than 12%, even more preferably less than 10%.Alternatively, the crystallinity is from 5% to 15%, or 5% to 10%.

FIG. 4 provides DSC results for the comparative and inventive examples.The DSC experiment is performed on a TA instruments Q2000 differentialscanning calorimeter, operating under a nitrogen flow. Samples of 8-10mg are sealed in aluminum pans are initially held at 25° C. for 1minute, and then heated to 300° C. at a rate of 10° C./minute. Thecold-crystallization peak temperature (T_(cc)) is determined from themaximum of the crystallization exotherm observed during the heatingscan. The value of [ΔHm−ΔHc] is determined by the instrument andaccompany software, which automatically integrates the peak area betweenΔHm and ΔHc. The percentage of crystallinity results are report in Table3 below.

TABLE 3 Percentage (%) of crystallinity of comparative example andinventive examples A and B are provided. Example T_(cc) (° C.) ΔHm (J/g)ΔHc (J/g) ΔHm − ΔHc ΔHm° (J/g) % crystal Comp. 102.51 39.65 11.87 27.78140.1 19.83% Invent. A 110.95 30.77 12.28 18.49 140.1 13.20% Invent. B132.26 23.27 11.33 11.94 140.1 8.52%

Without wishing to be bound by theory, the less percentage crystallinitysuggests the PET copolymer resin during the stretching/blow molding stepmay have more an amorphous phase thereby allowing the resin to betteroccupy a corner portion of the article mold. However, the percentagecrystallinity is high enough so that desirable barrier properties couldbe observed. In other word, it is desirable to have a balance of the“blowability” to provide improved well-defined corners while stillexhibiting a suitable barrier property of the rigid blow molded article.

Multilayer Article

The rigid article of the present invention comprises at least an outerlayer of an outer layer material, preferably wherein the outer layermaterial is a PET copolymer resin as characterized herein.Alternatively, the article may comprise one or more layers. The second(or third etc.) layer, of multilayer examples of the present invention,may be the same or different as the outer layer material. In thesemultilayer examples, these materials may include thermoplasticmaterials, preferably wherein the thermoplastic material may include oneor more selected consisting of polyethylene terephthalate (PET),polyethylene terephthalate glycol (PETG), polystyrene (PS),polycarbonate (PC), polyvinylchloride (PVC), polyethylene naphthalate(PEN), polycyclohexylenedimethylene terephthalate (PCT), glycol-modifiedPCT copolymer (PCTG), copolyester of cyclohexanedimethanol andterephthalic acid (PCTA), polybutylene terephthalate (PBT),acrylonitrile styrene (AS), styrene butadiene copolymer (SBC), andcombinations thereof.

Unless otherwise indicated, all percentages, ratios, and proportions arecalculated based on weight of the total composition. All temperaturesare in degrees Celsius (° C.) unless otherwise indicated. Allmeasurements made are at 25° C., unless otherwise designated. Allcomponent or composition levels are in reference to the active level ofthat component or composition, and are exclusive of impurities, forexample, residual solvents or by-products, which may be present incommercially available sources.

It should be understood that every maximum numerical limitation giventhroughout this specification includes every lower numerical limitation,as if such lower numerical limitations were expressly written herein.Every minimum numerical limitation given throughout this specificationwill include every higher numerical limitation, as if such highernumerical limitations were expressly written herein. Every numericalrange given throughout this specification will include every narrowernumerical range that falls within such broader numerical range, as ifsuch narrower numerical ranges were all expressly written herein.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application and any patent application or patent to which thisapplication claims priority or benefit thereof, is hereby incorporatedherein by reference in its entirety unless expressly excluded orotherwise limited. The citation of any document is not an admission thatit is prior art with respect to any invention disclosed or claimedherein or that it alone, or in any combination with any other referenceor references, teaches, suggests or discloses any such invention.Further, to the extent that any meaning or definition of a term in thisdocument conflicts with any meaning or definition of the same term in adocument incorporated by reference, the meaning or definition assignedto that term in this document shall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A rigid blow molded article comprising: sides ofthe article forming at least one corner wherein the corner ischaracterized by mathematically fitting a sphere of best fit into thecorner so there is a circular arc section in the at least one corner,wherein a radius of curvature of the sphere of best fit is less than 5.7mm; and the sides forming the corner comprises at least an outer layerof an outer layer material comprising PET copolymer resin, wherein theouter layer material having an elastic modulus (E′) less than about 370MPa measured by dynamical mechanical analysis per ASTM D4065, with afrequency sweep conducted at the fixed temperature of thecold-crystallization peak temperature (“T_(cc)”) of the PET copolymerresin minus 15° C. (T_(cc)−15° C. temperature) at 1 Hz, wherein theT_(cc) is measured by way of differential scanning calorimetry (“DSC”)at a temperature ramp rate of 10° C. per minute.
 2. The rigid blowmolded article container according to claim 1, wherein the radius ofcurvature of the sphere of best fit is less than 5 mm.
 3. The rigid blowmolded article container according to claim 1, wherein the E′ is at orless than about 300 MPa.
 4. The rigid blow molded article containeraccording to claim 1, wherein the corner comprises an average thicknessfrom about 0.2 mm to about 0.8 mm.
 5. The rigid blow molded articlecontainer according to claim 1, wherein the outer layer materialcomprises a T_(cc) greater than 105° C.
 6. The rigid blow molded articleaccording to claim 1, wherein the article is injection blow molded orinjected stretch blow molded.
 7. The rigid blow molded article accordingto claim 1, wherein the article is a container, and wherein thecontainer is capable of containing from 100 ml to 3,000 ml of contents.8. The rigid blow molded article of claim 1, wherein the corner havingan average thickness from about 0.1 mm to about 1 mm.
 9. The rigid blowmolded article according to claim 1, wherein the article is a bottle.10. The rigid blow molded article of claim 9, wherein the bottle is ashampoo bottle.
 11. The rigid blow molded article of claim 1, wherein:the radius of curvature of the sphere of best fit is from 2 mm to 4 mm;the E′ is from 60 MPa to 200 MPa; the outer layer material consistsessentially of a PET copolymer resin having a T_(cc) is from 120° C. to150° C., wherein the T_(cc) is measured by way of differential scanningcalorimetry at a temperature ramp rate of 10° C. per minute; and whereinthe article is a container, wherein the container contains a volume from300 ml to 1,200 ml.
 12. The blow molded article of claim 11, wherein theblow molded article is a shampoo bottle containing from 500 ml to 1,000ml of a shampoo composition suitable for cleaning hair.
 13. The rigidblow molded article of claim 12, wherein the shampoo bottle is injectionstretch blow molded at a temperature greater than 90° C., and at astretch ratio from 2 to
 8. 14. A rigid blow molded article comprising:sides of the article forming at least one corner wherein the corner ischaracterized by mathematically fitting a sphere of best fit into thecorner so there is a circular arc section in the at least one corner,wherein a radius of curvature of the sphere of best fit is less than 5.7mm; and the sides forming the corner comprises at least an outer layerof an outer layer material having an elastic modulus (E′) less thanabout 370 MPa measured by dynamical mechanical analysis per ASTM D4065,with a frequency sweep conducted at the fixed temperature of thecold-crystallization peak temperature (“T_(cc)”) of the outer layermaterial minus 15° C. (T_(cc)−15° C. temperature) at 1 Hz, wherein theT_(cc) is measured by way of differential scanning calorimetry (“DSC”)at a temperature ramp rate of 10° C. per minute.
 15. The rigid blowmolded article container according to claim 14, wherein the outer layermaterial comprises a polyethylene terephthalate (“PET”) copolymer resin.16. The rigid blow molded article container according to claim 15,wherein the PET copolymer resin comprises a T_(cc) greater than 105° C.17. The rigid blow molded article container according to claim 15,wherein the PET copolymer resin comprises a percentage of crystallinityof less than 19%, wherein the percentage of crystallinity is determinedby the formula: % crystallinity=[ΔHm−ΔHc]/ΔHm°*100%; wherein ΔHm is theheat of melting (J/g) and ΔHc is the heat of cold crystallization (J/g),and wherein ΔHm and ΔHc are determined by differential scanningcalorimetry at a temperature ramp rate of 10° C. per minute, and whereinΔHm° is reference value of 140.1 J/g.
 18. A rigid blow molded articlecomprising: sides of the article forming at least one corner wherein thecorner is characterized by mathematically fitting a sphere of best fitinto the corner so there is a circular arc section in the at least onecorner, wherein a radius of curvature of the sphere of best fit is lessthan 5.7 mm; and the sides forming the corner comprises at least anouter layer of an outer layer material having an elastic modulus (E′)less than about 370 MPa and a cold-crystallization peak temperature fromabout 120° C. to about 150° C. with a frequency sweep conducted at thefixed temperature of the cold-crystallization peak temperature of theouter layer material minus 15° C. (T_(cc)−15° C. temperature) at 1 Hz,wherein the Tcc is measured by way of differential scanning calorimetry(“DSC”) at a temperature ramp rate of 10° C. per minute.
 19. The rigidblow molded article of claim 18, wherein the outer layer materialcomprises a PET copolymer resin.
 20. The rigid blow molded article ofclaim 18, wherein the side forming the corner comprises a second layer.